A sieve is known for a centrifuge that has a drum which is rotated about an axis and is provided on its inside surface with a plurality of bars spaced radially inwardly from the inner surface of the drum and themselves forming a body of revolution centered on the rotation axis of the drum. The drum is perforated or otherwise foraminous and the bars are spaced circumferentially apart so that when spun at high speed, liquid and particles small enough to slip between the bars are driven centrifugally radially outwardly and the larger particles are trapped within the body of revolution formed by the inner surfaces of the bars. See German Gebrauchsmuster No. 1,928,975 and German Pat. No. 952,520.
When such a sieve is used in a centrifuge for heavy-duty dewatering or separation the solid fraction that is retained within the drum usually erodes the bars constituting this inner surface greatly. To this end these bars are usually fitted within the drum to holder rings each formed with a circumferential array of alternating notches and teeth. Each bar is fitted between two such rings within a notch in each of the rings and is secured in place there, usually by bolting at each end of each bar.
Since the circumferential spacing between the bars determines the size of the fraction retained within the centrifuge it is essential that the bars be exactly positioned relative to one another. It is also necessary to be able to replace worn bars with new ones in the event that the bars have worn so greatly that their spacing has increased beyond a permissible limit. In the above-described system it is therefore necessary to unbolt the separate bars and replace them individually in a complicated and time-consuming operation.
Another disadvantage of the known arrangement is that the support rings must be very carefully machined in order to maintain an accurate spacing between adjacent bars. Thus the support rings are relatively expensive. Furthermore the support rings are exposed at the gaps between the bars so that with time even these rings must be replaced, an operation which is not only difficult but entails considerable expense. Furthermore the bars are not reusable so that altogether new ones must be placed in the sieve for relining it.